*{
    margin: 0;
    padding: 0;
    font-family: "Microsoft Yahei";
}
body{
    display: flex;
    flex-direction: column;
    /*min-height: 100vh;*/
    height: 100%;
}
.dnull{
    width: 100%;
    text-align: center;
    line-height: 300px;
    font-weight: bold;
    font-size: 20px;
    color: #999;
}

/*导航栏*/
nav{
    width: 100%;
    height: 60px;
    background: #000;
    line-height: 60px;
}
/*logo*/
nav>img{
    width: 150px;
    height: 60px;
    margin-left: 40px;
}
#usermsg{
    float: right;
}
/*用户头像*/
#usericon{
    vertical-align: middle;
    margin-right: 20px;
    border-radius: 50%;
    border: 2px solid #999;
    cursor: pointer;
}
#user,#exist{
	color: #fff;
	text-decoration: none;
	margin-right: 20px;
}

/*用户信息*/
.user{
    width: 100%;
    height: auto;
    background: url("../images/bg.jpg");
    padding: 50px;
    box-sizing: border-box;
}
.usericon{
    width: 220px;
    height: 220px;
    left: 100px;
    border-radius: 50%;
    background: #fff;
    float: left;
    border: 3px solid #666;
}
.username{
    width: auto;
    height: auto;
    font-size: 40px;
    float: left;
    margin: 70px;
}

/*中间内容*/
.message{
    width: 1250px;
    flex: 1;
    margin: 0 auto;
    padding-top: 30px;
}
/*左侧导航*/
.catalog{
    width: 200px;
    height: auto;
    float: left;
}
ol li{
    height: 40px;
    margin: 30px 15px;
    border-bottom: 1px solid grey;
}
.color{
    color: #eb4f38;
}
.color2{
    color: #666;
}
.color3{
    color: #000;
}
.cata1,.cata2,.cata3{
    display: block;
    float: left;
    width: 118px;
    height: 40px;
    text-align: center;
    line-height: 40px;
    cursor: pointer;
    font-size: 17px;
}
.icon-ziyuan,.icon-tiwen,.icon-biji,.icon-youjiantou{
    font-size: 25px;
    line-height: 40px;
    float: left;
}
ol,ul{
    list-style: none;
}

/*页面内容*/
.content{
    min-height: 700px;
    float: right;
}

/*资源的内容*/
.course{
    /*display: none;*/
}
/*资源导航*/
.stu_following{
    width: 100%;
    height: 50px;
    border-bottom: 2px solid grey;
}
.course_cata1,.course_cata2{
    width: 65px;
    height: 50px;
    float: left;
    margin-right: 20px;
    line-height: 30px;
    cursor: pointer;
}
.addclass{
    border-bottom: 2px solid red;
    color: red;
}

/*最近学习+我的收藏*/
.cata1_,.cata2_{
    width: 1000px;
}
.cata2_{
    display: none;
}
.courses{
    width: 100%;
    height: auto;
    padding: 30px 50px;
    box-sizing: border-box;
    border-bottom: 1px solid grey;
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
}
.course_pic{
    width: 220px;
    height: 130px;
    background: #ccc;
    margin-right: 50px;
}
.courses_{
    width: 350px;
    height: 130px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    flex: 1;
}
.course_tit{
    font-size: 22px;
}
.course_mess>span,.course_note>span{
    margin-right: 50px;
}
.course_note>span>span{
    margin-left: 10px;
}
.course a{
    width: 100px;
    height: 40px;
    line-height: 40px;
    text-align: center;
    border: 1px solid #eb4f38;
    text-decoration: none;
    color: #eb4f38;
    display: block;
}
.course a:hover{
    background: #eb4f38;
    color: #fff;
}

/*提问*/
.question{
    display: none;
}
/*提问的目录*/
.q_cata{
    width: 1000px;
    height: 50px;
    border-bottom: 2px solid grey;
}
.q_q,.q_f{
    width: 65px;
    height: 50px;
    float: left;
    margin-right: 20px;
    line-height: 30px;
    cursor: pointer;
}
/*提问内容*/
/*.con1{
    display: none;
}*/
.q1{
    width: 1000px;
    height: auto;
    border-bottom: 1px solid grey;
    padding: 20px 40px;
    box-sizing: border-box;
}
.q1_icon{
    border-radius: 50%;
    border: 2px solid #999;
    margin-right: 20px;
}
.q1_msg{
    width: 90%;
    vertical-align: top;
    display: inline-block;
}
.msg_top{
    height: 45px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}
.q1_user{
    font-size: 12px;
    color: #999;
}
.q1_tit{
    width: 100%;
    color: #333;
    font-weight: bold;
    font-size: 17px;
}
.bot_ans,.bot_msg{
    color: #666;
    margin-top: 10px;
    font-size: 15px;
}
.bot_ans>span:nth-child(1){
    font-weight: bold;
    margin-right: 10px;
}
.bot_msg{
    font-size: 12px;
    display: flex;
    justify-content: space-between;
}
.bot_msg>span:nth-child(2)>span{
    margin-left: 5px;
}
/*我的回答*/
.con2{
    display: none;
    width: 1000px;
    position: relative;
}
.con2_a1{
    width: 100%;
    height: auto;
    padding: 20px 40px;
    box-sizing: border-box;
    border-bottom: 1px solid grey;
}
.q1_a2{
    width: auto;
    margin-top: 30px;
    display: flex;
    font-size: 15px;
    color: #666;
    justify-content: space-between;
}
.q1_a2>span>span{
    margin-left: 10px;
}

/*笔记*/
.note{
    display: none;
}
.note_my{
    width: 1000px;
    height: 50px;
    line-height: 40px;
    border-bottom: 2px solid grey;
}
/*笔记内容*/
.note1{
    width: 1000px;
    height: auto;
    border-bottom: 1px solid grey;
    padding: 20px 40px;
    box-sizing: border-box;
}
.note_course{
    height: 25px;
    font-size: 12px;
    color: #999;
    display: flex;
    justify-content: space-between;
}
.note_tit{
    width: auto;
    height: 40px;
    font-size: 20px;
    cursor: pointer;
}
.note_con{
    width: auto;
    min-height: 105px;
    border: 1px solid grey;
    color: #666;
    /*overflow: hidden;*/
    padding: 10px;
    box-sizing: border-box;
}

/*版权信息*/
footer{
    width: 100%;
    height: 80px;
    background: black;
    margin-top: 70px;
    color: #fff;
    line-height: 80px;
    text-align: center;
    font-size: 14px;
}

/*返回顶部*/
.backToTop{
    width: 50px;
    height: 50px;
    font-size: 45px;
    text-align: center;
    position: fixed;
    bottom: 20px;
    right: 20px;
    display: none;
    background: #999;
    color: #fff;
    border-radius: 5px;
    cursor: pointer;
}